Electronic devices such as various mobile phones and TVs have been developed. These electronic devices are equipped with a printed circuit board (PCB) with various parts, which are components enabling operation of the electronic devices, mounted therein.
A light emitting diode (hereafter, referred to as an LED), which is a diode that emits light when a current is supplied, is a light emitting device in which electrons are excited to a higher energy level when a small number of carriers are injected into an active layer and the energy of the electrons is emitted as electromagnetic waves having the wavelength of light when the electrons return to the stable state.
Recently, LEDs can be manufactured with high luminance and quality over a common product with low brightness by virtue of rapid development of semiconductor technology. Further, as high-performance blue and white diodes can be implemented, the availability of LEDs is being expanded to advance lighting sources, various displays etc. A device formed in a predetermined size by a single LED or by coupling a plurality of LEDs is called an LED module, which is used for various displays and imaging devices.